Commit Graph

57 Commits

Author SHA1 Message Date
James Clark 0a98181f80 coresight: Make new csdev_access offsets unsigned
New csdev_access functions were added as part of the previous
refactor. In order to make them more consistent with the
existing ones, change any signed offset types to be unsigned.

Now that they are unsigned, stop using hi_off = -1 to signify
a single 32bit access. Instead just call the existing 32bit
accessors. This is also applied to other parts of the codebase,
and the coresight_{read,write}_reg_pair() functions can be
deleted.

Signed-off-by: James Clark <james.clark@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Link: https://lore.kernel.org/r/20220830172614.340962-6-james.clark@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
2022-08-31 10:56:36 -06:00
James Clark b6df1cbb41 coresight: Simplify sysfs accessors by using csdev_access abstraction
The coresight_device struct is available in the sysfs accessor, and this
contains a csdev_access struct which can be used to access registers.
Use this instead of passing in the type of each drvdata so that a common
function can be shared between all the cs drivers.

No functional changes.

Signed-off-by: James Clark <james.clark@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Link: https://lore.kernel.org/r/20220830172614.340962-3-james.clark@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
2022-08-31 10:54:59 -06:00
Anshuman Khandual 286f950545 coresight: Drop unused 'none' enum value for each component
CORESIGHT_DEV_TYPE_NONE/CORESIGHT_DEV_SUBTYPE_XXXX_NONE values are not used
any where. Actual enumeration can start from 0. Just drop these unused enum
values.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/1645005118-10561-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
2022-03-11 10:07:57 +00:00
Mike Leach f8cce2ff3c coresight: syscfg: Add API to activate and enable configurations
Configurations are first activated, then when any coresight device is
enabled, the active configurations are checked and any matching
one is enabled.

This patch provides the activation / enable API.

Link: https://lore.kernel.org/r/20210723165444.1048-6-mike.leach@linaro.org
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20210818194022.379573-6-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-18 22:33:28 +02:00
Mike Leach 42ff700f31 coresight: syscfg: Add registration and feature loading for cs devices
API for individual devices to register with the syscfg management
system is added.

Devices register with matching information, and any features or
configurations that match will be loaded into the device.

The feature and configuration loading is extended so that on load these
are loaded into any currently registered devices. This allows
configuration loading after devices have been registered.

Link: https://lore.kernel.org/r/20210723165444.1048-3-mike.leach@linaro.org
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20210818194022.379573-3-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-18 22:33:27 +02:00
Anshuman Khandual 2cd87a7b29 coresight: core: Add support for dedicated percpu sinks
Add support for dedicated sinks that are bound to individual CPUs. (e.g,
TRBE). To allow quicker access to the sink for a given CPU bound source,
keep a percpu array of the sink devices. Also, add support for building
a path to the CPU local sink from the ETM.

This adds a new percpu sink type CORESIGHT_DEV_SUBTYPE_SINK_PERCPU_SYSMEM.
This new sink type is exclusively available and can only work with percpu
source type device CORESIGHT_DEV_SUBTYPE_SOURCE_PROC.

This defines a percpu structure that accommodates a single coresight_device
which can be used to store an initialized instance from a sink driver. As
these sinks are exclusively linked and dependent on corresponding percpu
sources devices, they should also be the default sink device during a perf
session.

Outwards device connections are scanned while establishing paths between a
source and a sink device. But such connections are not present for certain
percpu source and sink devices which are exclusively linked and dependent.
Build the path directly and skip connection scanning for such devices.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
[Moved the set/get percpu sink APIs from TRBE patch to here
 Fixed build break on arm32]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20210405164307.1720226-17-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
2021-04-06 16:05:38 -06:00
Suzuki K Poulose 8ce0029658 coresight: Convert claim/disclaim operations to use access wrappers
Convert the generic CLAIM tag management APIs to use the
device access layer abstraction.

Link: https://lore.kernel.org/r/20210110224850.1880240-7-suzuki.poulose@arm.com
Cc: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20210201181351.1475223-9-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-02-04 17:00:32 +01:00
Suzuki K Poulose 020052825e coresight: Convert coresight_timeout to use access abstraction
Convert the generic routines to use the new access abstraction layer
gradually, starting with coresigth_timeout.

Link: https://lore.kernel.org/r/20210110224850.1880240-6-suzuki.poulose@arm.com
Cc: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20210201181351.1475223-8-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-02-04 17:00:32 +01:00
Suzuki K Poulose 6e736c60a9 coresight: Introduce device access abstraction
We are about to introduce support for sysreg access to ETMv4.4+
component. Since there are generic routines that access the
registers (e.g, CS_LOCK/UNLOCK , claim/disclaim operations, timeout)
and in order to preserve the logic of these operations at a
single place we introduce an abstraction layer for the accesses
to a given device.

Link: https://lore.kernel.org/r/20210110224850.1880240-4-suzuki.poulose@arm.com
Cc: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20210201181351.1475223-6-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-02-04 17:00:32 +01:00
Tingwei Zhang f2ccc7b7bf coresight: cti: Don't disable ect device if it's not enabled
If associated ect device is not enabled at first place, disable
routine should not be called. Add ect_enabled flag to check whether
ect device is enabled. Fix the issue in below case.  Ect device is
not available when associated coresight device enabled and the
association is established after coresight device is enabled.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200928163513.70169-20-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-28 19:47:41 +02:00
Kim Phillips b8127113d0 coresight: Use IS_ENABLED for CONFIGs that may be modules
Checking for ifdef CONFIG_x fails if CONFIG_x=m.  Use IS_ENABLED
that is true for both built-ins and modules, instead.  Required
when building coresight components as modules.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Suzuki K Poulose <Suzuki.Poulose@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Russell King <linux@armlinux.org.uk>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Kim Phillips <kim.phillips@arm.com>
Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200928163513.70169-4-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-28 19:47:40 +02:00
Mike Leach 0336bdfd73 coresight: Add default sink selection to CoreSight base
Adds a method to select a suitable sink connected to a given source.

In cases where no sink is defined, the coresight_find_default_sink
routine can search from a given source, through the child connections
until a suitable sink is found.

The suitability is defined in by the sink coresight_dev_subtype on the
CoreSight device, and the distance from the source by counting
connections.

Higher value subtype is preferred - where these are equal, shorter
distance from source is used as a tie-break.

This allows for default sink to be discovered were none is specified
(e.g. perf command line)

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200716175746.3338735-15-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-21 15:48:40 +02:00
Mike Leach d061cd734f coresight: Fix comment in main header file
Comment for an elemnt in the coresight_device structure appears to have
been corrupted and makes no sense. Fix this before making further changes.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200716175746.3338735-12-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-21 15:48:39 +02:00
Suzuki K Poulose d375b356e6 coresight: Fix support for sparsely populated ports
On some systems the firmware may not describe all the ports
connected to a component (e.g, for security reasons). This
could be especially problematic for "funnels" where we could
end up in modifying memory beyond the allocated space for
refcounts.

e.g, for a funnel with input ports listed 0, 3, 5, nr_inport = 3.
However the we could access refcnts[5] while checking for
references, like :

 [  526.110401] ==================================================================
 [  526.117988] BUG: KASAN: slab-out-of-bounds in funnel_enable+0x54/0x1b0
 [  526.124706] Read of size 4 at addr ffffff8135f9549c by task bash/1114
 [  526.131324]
 [  526.132886] CPU: 3 PID: 1114 Comm: bash Tainted: G S                5.4.25 #232
 [  526.140397] Hardware name: Qualcomm Technologies, Inc. SC7180 IDP (DT)
 [  526.147113] Call trace:
 [  526.149653]  dump_backtrace+0x0/0x188
 [  526.153431]  show_stack+0x20/0x2c
 [  526.156852]  dump_stack+0xdc/0x144
 [  526.160370]  print_address_description+0x3c/0x494
 [  526.165211]  __kasan_report+0x144/0x168
 [  526.169170]  kasan_report+0x10/0x18
 [  526.172769]  check_memory_region+0x1a4/0x1b4
 [  526.177164]  __kasan_check_read+0x18/0x24
 [  526.181292]  funnel_enable+0x54/0x1b0
 [  526.185072]  coresight_enable_path+0x104/0x198
 [  526.189649]  coresight_enable+0x118/0x26c

  ...

 [  526.237782] Allocated by task 280:
 [  526.241298]  __kasan_kmalloc+0xf0/0x1ac
 [  526.245249]  kasan_kmalloc+0xc/0x14
 [  526.248849]  __kmalloc+0x28c/0x3b4
 [  526.252361]  coresight_register+0x88/0x250
 [  526.256587]  funnel_probe+0x15c/0x228
 [  526.260365]  dynamic_funnel_probe+0x20/0x2c
 [  526.264679]  amba_probe+0xbc/0x158
 [  526.268193]  really_probe+0x144/0x408
 [  526.271970]  driver_probe_device+0x70/0x140

 ...

 [  526.316810]
 [  526.318364] Freed by task 0:
 [  526.321344] (stack is not available)
 [  526.325024]
 [  526.326580] The buggy address belongs to the object at ffffff8135f95480
 [  526.326580]  which belongs to the cache kmalloc-128 of size 128
 [  526.339439] The buggy address is located 28 bytes inside of
 [  526.339439]  128-byte region [ffffff8135f95480, ffffff8135f95500)
 [  526.351399] The buggy address belongs to the page:
 [  526.356342] page:ffffffff04b7e500 refcount:1 mapcount:0 mapping:ffffff814b00c380 index:0x0 compound_mapcount: 0
 [  526.366711] flags: 0x4000000000010200(slab|head)
 [  526.371475] raw: 4000000000010200 ffffffff05034008 ffffffff0501eb08 ffffff814b00c380
 [  526.379435] raw: 0000000000000000 0000000000190019 00000001ffffffff 0000000000000000
 [  526.387393] page dumped because: kasan: bad access detected
 [  526.393128]
 [  526.394681] Memory state around the buggy address:
 [  526.399619]  ffffff8135f95380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 [  526.407046]  ffffff8135f95400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 [  526.414473] >ffffff8135f95480: 04 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 [  526.421900]                             ^
 [  526.426029]  ffffff8135f95500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 [  526.433456]  ffffff8135f95580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 [  526.440883] ==================================================================

To keep the code simple, we now track the maximum number of
possible input/output connections to/from this component
@ nr_inport and nr_outport in platform_data, respectively.
Thus the output connections could be sparse and code is
adjusted to skip the unspecified connections.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Reported-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Tested-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-13-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-19 16:31:16 +02:00
Suzuki K Poulose 8a7365c2d4 coresight: Expose device connections via sysfs
Coresight device connections are a bit complicated and is not
exposed currently to the user. One has to look at the platform
descriptions (DT bindings or ACPI bindings) to make an understanding.
Given the new naming scheme, it will be helpful to have this information
to choose the appropriate devices for tracing. This patch exposes
the device connections via links in the sysfs directories.

e.g, for a connection devA[OutputPort_X] -> devB[InputPort_Y]
is represented as two symlinks:

  /sys/bus/coresight/.../devA/out:X -> /sys/bus/coresight/.../devB
  /sys/bus/coresight/.../devB/in:Y  -> /sys/bus/coresight/.../devA

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
[Revised to use the generic sysfs links functions & link structures.
Provides a connections sysfs group in each device to hold the links.]
Co-developed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-5-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-19 16:31:15 +02:00
Mike Leach 8096152588 coresight: Add generic sysfs link creation functions
To allow the connections between coresight components to be represented
in sysfs, generic methods for creating sysfs links between two coresight
devices are added.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-4-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-19 16:31:15 +02:00
Mike Leach 177af8285b coresight: cti: Enable CTI associated with devices
The CoreSight subsystem enables a path of devices from source to sink.
Any CTI devices associated with the path devices must be enabled at the
same time.

This patch adds an associated coresight_device element to the main
coresight device structure, and uses this to create associations between
the CTI and other devices based on the device tree data. The associated
device element is used to enable CTI in conjunction with the path elements.

CTI devices are reference counted so where a single CTI is associated with
multiple elements on the path, it will be enabled on the first associated
device enable, and disabled with the last associated device disable.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200320165303.13681-9-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-21 11:32:20 +01:00
Mike Leach 835d722ba1 coresight: cti: Initial CoreSight CTI Driver
This introduces a baseline CTI driver and associated configuration files.

Uses the platform agnostic naming standard for CoreSight devices, along
with a generic platform probing method that currently supports device
tree descriptions, but allows for the ACPI bindings to be added once these
have been defined for the CTI devices.

Driver will probe for the device on the AMBA bus, and load the CTI driver
on CoreSight ID match to CTI IDs in tables.

Initial sysfs support for enable / disable provided.

Default CTI interconnection data is generated based on hardware
register signal counts, with no additional connection information.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200320165303.13681-2-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-21 11:32:18 +01:00
Andrew Murray f188b5e76a coresight: etm4x: Save/restore state across CPU low power states
Some hardware will ignore bit TRCPDCR.PU which is used to signal
to hardware that power should not be removed from the trace unit.
Let's mitigate against this by conditionally saving and restoring
the trace unit state when the CPU enters low power states.

This patchset introduces a firmware property named
'arm,coresight-loses-context-with-cpu' - when this is present the
hardware state will be conditionally saved and restored.

A module parameter 'pm_save_enable' is also introduced which can
be configured to override the firmware property. This can be set
to never allow save/restore or to conditionally allow it (only for
self-hosted). The default value is determined by firmware.

We avoid saving the hardware state when self-hosted coresight isn't
in use to reduce PM latency - we can't determine this by reading the
claim tags (TRCCLAIMCLR) as these are 'trace' registers which need
power and clocking, something we can't easily provide in the PM
context. Therefore we rely on the existing drvdata->mode internal
state that is set when self-hosted coresight is used (and powered).

Signed-off-by: Andrew Murray <andrew.murray@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20191104181251.26732-2-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-04 21:57:51 +01:00
Suzuki K Poulose 0f5f9b6ba9 coresight: Use platform agnostic names
So far we have reused the name of the "platform" device for
the CoreSight device. But this is not very intuitive when
we move to ACPI. Also, the ACPI device names have ":" in them
(e.g, ARMHC97C:01), which the perf tool doesn't like very much.
This patch introduces a generic naming scheme, givin more intuitive
names for the devices that appear on the CoreSight bus.
The names follow the pattern "prefix" followed by "index" (e.g, etm5).
We maintain a list of allocated devices per "prefix" to make sure
we don't allocate a new name when it is reprobed (e.g, due to
unsatisifed device dependencies). So, we maintain the list
of "fwnodes" of the parent devices to allocate a consistent name.
All devices except the ETMs get an index allocated in the order
of probing. ETMs get an index based on the CPU they are attached to.

TMC devices are named using "tmc_etf", "tmc_etb", and "tmc_etr"
prefixes depending on the configuration of the device.

The replicators and funnels are not classified as dynamic/static
anymore. One could easily figure that out by checking the presence
of "mgmt" registers under sysfs.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-20 07:56:13 +02:00
Suzuki K Poulose 37ea1ffddf coresight: Use fwnode handle instead of device names
We rely on the device names to find a CoreSight device on the
coresight bus. The device name however is obtained from the platform,
which is bound to the real platform/amba device. As we are about
to use different naming scheme for the coresight devices, we can't
rely on the platform device name to find the corresponding
coresight device. Instead we use the platform agnostic
"fwnode handle" of the parent device to find the devices.
We also reuse the same fwnode as the parent for the Coresight
device we create.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-20 07:56:13 +02:00
Suzuki K Poulose b77e3ed038 coresight: Reuse platform data structure for connection tracking
The platform specific information describes the connections and
the ports of a given coresigh device. This information is also
recorded in the coresight device as separate fields. Let us reuse
the original platform description to streamline the handling
of the data.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-20 07:56:12 +02:00
Suzuki K Poulose 2ede79a6e8 coresight: Remove name from platform description
We are about to use a name independent of the parent AMBA device
name. As such, there is no need to have it in the platform description.
Let us move this to coresight description instead.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-20 07:56:12 +02:00
Suzuki K Poulose aff70a45fe coresight: Remove cpu field from platform data
CPU field is only used by ETMs and there is a separate API
for fetching the same. So, let us use that instead of using
the common platform probing helper. Also, remove it from the
platform_data.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-20 07:56:12 +02:00
Suzuki K Poulose 91824db2ea coresight: Make device to CPU mapping generic
The CoreSight components ETM and CPU-Debug are always associated
with CPUs. Replace the of_coresight_get_cpu() with a platform
agnostic helper, in preparation to add ACPI support.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-20 07:56:11 +02:00
Suzuki K Poulose f03631da4b coresight: Introduce generic platform data helper
So far we have hard coded the DT platform parsing code in
every driver. Introduce generic helper to parse the information
provided by the firmware in a platform agnostic manner, in preparation
for the ACPI support.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-20 07:56:11 +02:00
Mathieu Poirier a0f08a6a9f coresight: Communicate perf event to sink buffer allocation functions
Make struct perf_event available to sink buffer allocation functions in
order to use the pid they carry to allocate and free buffer memory along
with regimenting access to what source a sink can collect data for.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Tested-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Robert Walker <robert.walker@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-25 22:00:17 +02:00
Mathieu Poirier 6c817a95d8 coresight: Adding return code to sink::disable() operation
In preparation to handle device reference counting inside of the sink
drivers, add a return code to the sink::disable() operation so that
proper action can be taken if a sink has not been disabled.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Tested-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Robert Walker <robert.walker@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-25 22:00:16 +02:00
Mathieu Poirier bb8e370bdc coresight: perf: Add "sinks" group to PMU directory
Add a "sinks" directory entry so that users can see all the sinks
available in the system in a single place.  Individual sink are added
as they are registered with the coresight bus.

Committer tests:

Test built on a ubuntu 18.04 container with a cross build environment to
arm64, the new field is there, need to find a machine with this feature
to do further testing in the future.

  root@d15263e5734a:/git/perf# grep CORESIGHT /tmp/build/v5.0-rc2+/.config
  CONFIG_CORESIGHT=y
  CONFIG_CORESIGHT_LINKS_AND_SINKS=y
  CONFIG_CORESIGHT_LINK_AND_SINK_TMC=y
  CONFIG_CORESIGHT_CATU=y
  CONFIG_CORESIGHT_SINK_TPIU=y
  CONFIG_CORESIGHT_SINK_ETBV10=y
  CONFIG_CORESIGHT_SOURCE_ETM4X=y
  CONFIG_CORESIGHT_DYNAMIC_REPLICATOR=y
  CONFIG_CORESIGHT_STM=y
  CONFIG_CORESIGHT_CPU_DEBUG=m
  root@d15263e5734a:/git/perf#
  root@d15263e5734a:/git/perf# file /tmp/build/v5.0-rc2+/drivers/hwtracing/coresight/*.o
  .../coresight/coresight-catu.o:               ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  .../coresight/coresight-cpu-debug.mod.o:      ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  .../coresight/coresight-cpu-debug.o:          ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  .../coresight/coresight-dynamic-replicator.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  .../coresight/coresight-etb10.o:              ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  .../coresight/coresight-etm-perf.o:           ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  .../coresight/coresight-etm4x-sysfs.o:        ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  .../coresight/coresight-etm4x.o:              ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  .../coresight/coresight-funnel.o:             ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  .../coresight/coresight-replicator.o:         ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  .../coresight/coresight-stm.o:                ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  .../coresight/coresight-tmc-etf.o:            ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  .../coresight/coresight-tmc-etr.o:            ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  .../coresight/coresight-tmc.o:                ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  .../coresight/coresight-tpiu.o:               ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  .../coresight/coresight.o:                    ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  .../coresight/of_coresight.o:                 ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
  root@d15263e5734a:/git/perf#

  root@d15263e5734a:/git/perf# pahole -C coresight_device /tmp/build/v5.0-rc2+/drivers/hwtracing/coresight/coresight.o
  struct coresight_device {
          struct coresight_connection * conns;             /*     0     8 */
          int                        nr_inport;            /*     8     4 */
          int                        nr_outport;           /*    12     4 */
          enum coresight_dev_type    type;                 /*    16     4 */
          union coresight_dev_subtype subtype;             /*    20     8 */

          /* XXX 4 bytes hole, try to pack */

          const struct coresight_ops  * ops;               /*    32     8 */
          struct device              dev;                  /*    40  1408 */

          /* XXX last struct has 7 bytes of padding */

          /* --- cacheline 22 boundary (1408 bytes) was 40 bytes ago --- */
          atomic_t *                 refcnt;               /*  1448     8 */
          bool                       orphan;               /*  1456     1 */
          bool                       enable;               /*  1457     1 */
          bool                       activated;            /*  1458     1 */

          /* XXX 5 bytes hole, try to pack */

          struct dev_ext_attribute * ea;                   /*  1464     8 */

          /* size: 1472, cachelines: 23, members: 12 */
          /* sum members: 1463, holes: 2, sum holes: 9 */
          /* paddings: 1, sum paddings: 7 */
  };
  root@d15263e5734a:/git/perf#

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Link: http://lkml.kernel.org/r/20190131184714.20388-3-mathieu.poirier@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-02-06 10:00:39 -03:00
Suzuki K Poulose 2478a6ae4a coresight: Add support for CLAIM tag protocol
Coresight architecture defines CLAIM tags for a device to negotiate
control of the components (external agent vs self-hosted). Each device
has a pair of registers (CLAIMSET & CLAIMCLR) for managing the CLAIM
tags. However, the protocol for the CLAIM tags is IMPLEMENTATION DEFINED.
PSCI has recommendations for the use of the CLAIM tags to negotiate
controls for external agent vs self-hosted use. This patch implements
the recommended protocol by PSCI.

The claim/disclaim operations are performed from the device specific
drivers. The disadvantage is that the calls are sprinkled in each driver,
but this makes the operation much simpler.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-25 20:09:19 +02:00
Suzuki K Poulose 3d6e893575 coresight: perf: Remove set_buffer call back
In coresight perf mode, we need to prepare the sink before
starting a session, which is done via set_buffer call back.
We then proceed to enable the tracing. If we fail to start
the session successfully, we leave the sink configuration
unchanged.  In order to make the operation atomic and to
avoid yet another call back to clear the buffer, we get
rid of the "set_buffer" call back and pass the buffer details
via enable() call back to the sink.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-25 20:09:18 +02:00
Suzuki K Poulose 7ec786ad19 coresight: perf: Remove reset_buffer call back for sinks
Right now we issue an update_buffer() and reset_buffer() call backs
in succession when we stop tracing an event. The update_buffer is
supposed to check the status of the buffer and make sure the ring buffer
is updated with the trace data. And we store information about the
size of the data collected only to be consumed by the reset_buffer
callback which always follows the update_buffer. This was originally
designed for handling future IPs which could trigger a buffer overflow
interrupt. This patch gets rid of the reset_buffer callback altogether
and performs the actions in update_buffer, making it return the size
collected. We can always add the support for handling the overflow
interrupt case later.

This removes some not-so pretty hack (storing the new head in the
size field for snapshot mode) and cleans it up a little bit.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-25 20:09:18 +02:00
Suzuki K Poulose c2c729415b coresight: platform: Cleanup coresight connection handling
The platform code parses the component connections and populates
a platform-description of the output connections in arrays of fields
(which is never freed). This is later copied in the coresight_register
to a newly allocated area, represented by coresight_connection(s).

This patch cleans up the code dealing with connections by making
use of the "coresight_connection" structure right at the platform
code and lets the generic driver simply re-use information provided
by the platform.

Thus making it reader friendly as well as avoiding the wastage of
unused memory.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-25 20:09:17 +02:00
Suzuki K Poulose fcacb5c154 coresight: Introduce support for Coresight Address Translation Unit
Add the initial support for Coresight Address Translation Unit, which
augments the TMC in Coresight SoC-600 by providing an improved Scatter
Gather mechanism. CATU is always connected to a single TMC-ETR and
converts the AXI address with a translated address (from a given SG
table with specific format). The CATU should be programmed in pass
through mode and enabled even if the ETR doesn't use the translation
by CATU.

This patch provides mechanism to enable/disable the CATU always in the
pass through mode.

We reuse the existing ports mechanism to link the TMC-ETR to the
connected CATU.

i.e, TMC-ETR:output_port0 -> CATU:input_port0

Reference manual for CATU component is avilable in version r2p0 of :
"Arm Coresight System-on-Chip SoC-600 Technical Reference Manual".

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-15 13:52:58 +02:00
Suzuki K Poulose 8a091d847c coresight: Add helper device type
Add a new coresight device type, which do not belong to any
of the existing types, i.e, source, sink, link etc. A helper
device could be connected to a coresight device, which could
augment the functionality of the coresight device.

This is intended to cover Coresight Address Translation Unit (CATU)
devices, which provide improved Scatter Gather mechanism for TMC
ETR. The idea is that the helper device could be controlled by
the driver of the device it is attached to (in this case ETR),
transparent to the generic coresight driver (and paths).

The operations include enable(), disable(), both of which could
accept a device specific "data" which the driving device and
the helper device could share. Since they don't appear in the
coresight "path" tracked by software, we have to ensure that
they are powered up/down whenever the master device is turned
on.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-15 13:52:58 +02:00
Suzuki K Poulose 00b78e8b7b coresight: Cleanup device subtype struct
Clean up our struct a little bit by using a union instead of
a struct for tracking the subtype of a device.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-15 13:52:58 +02:00
Suzuki K Poulose 5756949782 coresight: Cleanup platform description data
Nobody uses the "clk" field in struct coresight_platform_data.
Remove it.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-15 13:52:58 +02:00
Mathieu Poirier 25b4a2b909 coresight: Remove function coresight_vpid_to_pid()
Now that we prevent users from using contextID tracing when PID namespaces
are involved there is no client for function coresight_vpid_to_pid().  As
such simply remove it.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Kim Phillips <kim.phillips@arm.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-15 13:52:56 +02:00
Mathieu Poirier ad0dfdfd87 coresight: Moving framework and drivers to SPDX identifier
Moving all kernel side CoreSight framework and drivers to SPDX identifier.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-14 16:19:59 +02:00
Leo Yan c56cdd7a5c coresight: refactor with function of_coresight_get_cpu
This is refactor to add function of_coresight_get_cpu(), so it's used to
retrieve CPU id for coresight component. Finally can use it as a common
function for multiple places.

Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09 11:45:25 +02:00
Leo Yan f42fe520e4 coresight: use const for device_node structures
Almost low level functions from open firmware have used const to
qualify device_node structures, so add const for device_node
parameters in of_coresight related functions.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09 11:45:24 +02:00
Will Deacon f4c0b0aa58 perf/core: Keep AUX flags in the output handle
In preparation for adding more flags to perf AUX records, introduce a
separate API for setting the flags for a session, rather than appending
more bool arguments to perf_aux_output_end. This allows to set each
flag at the time a corresponding condition is detected, instead of
tracking it in each driver's private state.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/20170220133352.17995-3-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-16 09:51:10 +01:00
Mathieu Poirier 68905d73df coresight: etm-perf: pass struct perf_event to source::enable/disable()
With this commit [1] address range filter information is now found
in the struct hw_perf_event::addr_filters.  As such pass the event
itself to the coresight_source::enable/disable() functions so that
both event attribute and filter can be accessible for configuration.

[1] 'commit 375637bc52 ("perf/core: Introduce address range filtering")'

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-08-31 13:05:43 +02:00
Mathieu Poirier 2997aa4063 coresight: etb10: implementing AUX API
Adding an ETB10 specific AUX area operations to be used
by the perf framework when events are initialised.

Part of this operation involves modeling the mmap'ed area
based on the specific ways a sink buffer gathers information.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-20 14:11:01 -08:00
Mathieu Poirier e827d4550a coresight: etb10: adding operation mode for sink->enable()
Adding an operation mode to the sink->enable() API in order
to prevent simultaneous access from different callers.

TPIU and TMC won't be supplemented with the AUX area
API immediately and as such ignore the new mode.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-20 14:11:01 -08:00
Mathieu Poirier 882d5e1124 coresight: etm3x: implementing perf_enable/disable() API
That way traces can be enabled and disabled automatically
from the Perf subystem using the PMU abstraction.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-20 14:11:01 -08:00
Mathieu Poirier 22fd532eaa coresight: etm3x: adding operation mode for etm_enable()
Adding a new mode to source API enable() in order to
distinguish where the request comes from.  That way it is
possible to perform different operations based on where
the request was issued from.

The ETM4x driver is also modified to keep in sync with the
new interface.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-20 14:11:01 -08:00
Mathieu Poirier b3e9440594 coresight: associating path with session rather than tracer
When using the Coresight framework from the sysFS interface a
tracer is always handling a single session and as such, a path
can be associated with a tracer.  But when supporting multiple
session per tracer there is no guarantee that sessions will always
have the same path from source to sink.

This patch is removing the automatic association between path and
tracers.  The building of a path and enablement of the components
in the path are decoupled, allowing for the association of a path
with a session rather than a tracer.

To keep backward functionality with the current sysFS access methods
a per-cpu place holder is used to keep a handle on the path built when
tracers are enabled.  Lastly APIs to build paths and enable tracers are
made public so that other subsystem can interact with the Coresight
framework.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-20 14:11:01 -08:00
Mathieu Poirier 52210c8745 coresight: implementing 'cpu_id()' API
Other than plainly parsing the device tree there is no way to
know which CPU a tracer is affined to.  As such adding an
interface to lookup the CPU field enclosed in the etm_drvdata
structure that was initialised at boot time.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-07 22:12:18 -08:00
Mathieu Poirier 1d27ff5aba coresight: fixing typographical error
Tracing gets enabled _for_ a source rather than _from_ a source.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-07 17:54:09 +01:00